| Table 1. A comparison of vectors in use for clinical gene transfer (tab001jfo) |
|
|
Application for human use |
|
|
|
| Vector classification |
Ex
vivo |
In
vivo |
Expression |
Advantages |
Disadvantages |
| Viral |
| Recombinant Moloney murine leukaemia virus (MMLV; retrovirus) |
+++ |
++ |
Stable |
No immune response against the viral vector; integrates |
Only low viral titres achieved; transduces only dividing cells |
| Recombinant lentivirus (retrovirus) |
+ |
+ |
Stable |
Transduces non-dividing cells; can target CD4+ T cells |
Potential safety risk |
| Recombinant adenovirus |
+++ |
++ |
Transient |
High viral titre; wide host-cell range |
Immunogenic; does not integrate; short-term transgene expression |
| Recombinant adeno-associated virus |
+++ |
++ |
Stable |
Little immunogenicity; integrates |
Lower transduction efficiency than adenovirus |
| Recombinant herpes simplex virus (HSV) |
++ (research) |
++ |
Not known |
Can target neuronal tissue |
Safety concerns |
| Recombinant vaccinia virus |
+/- |
+++ |
Transient |
Suitable for cancer gene therapy |
Safety concerns |
| Non viral |
| DNA-ligand conjugates |
- |
++ |
Transient |
Cell-specific targeting |
|
| Liposomes and virosomes |
++ |
+++ |
Stable or transient |
Cell-specific targeting; efficient transfection |
|
| Direct DNA injection |
- |
++ |
Transient |
Simple |
Only short-term expression achieved |
| Ballistic delivery (gene gun) |
++ (research) |
+/- |
Transient |
Simple |
Requires ‘exposed’ tissues or cells |
| Abbreviations used: ‘+++’ = major application; ‘++’ = some application; ‘+/-’ = limited application; ‘-’ = no application. |